package com.vains.filter;

import com.vains.dto.AuthorityDto;
import com.vains.util.JsonUtils;
import com.vains.util.JwtUtils;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.web.authentication.www.BasicAuthenticationFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.*;

/**
 *
 * 登录成功之后走此类进行解析token并生成一个认证信息
 */
public class JWTAuthorizationFilter extends BasicAuthenticationFilter {

    public JWTAuthorizationFilter(AuthenticationManager authenticationManager) {
        super(authenticationManager);
    }

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException {

        String tokenHeader = request.getHeader("token");
        // 如果请求头中没有Authorization信息则直接放行了
        if (tokenHeader == null) {
            chain.doFilter(request, response);
            return;
        }
        // 如果请求头中有token，则进行解析，并且设置认证信息
        SecurityContextHolder.getContext().setAuthentication(getAuthentication(tokenHeader));
        super.doFilterInternal(request, response, chain);
    }

    // 这里从token中获取用户信息并新建一个token
    private UsernamePasswordAuthenticationToken getAuthentication(String tokenHeader) {
        Map<String, Object> subject = JwtUtils.getSubject(tokenHeader, "123456");
        Set<AuthorityDto> authorities = JsonUtils.objectCovertToObject(subject.get("authorities"), Set.class, AuthorityDto.class);
        String username = (String) subject.get("username");
        if (username != null){
            return new UsernamePasswordAuthenticationToken(username, null,
                    authorities
            );
        }
        return null;
    }
}
